Complex construction delays Peace BridgeIs it just me or does this look like a complete embarrassment? This isn't the first report of delays on Calatrava's Calgary footbridge caused by fabrication difficulties. Here, the critical need for strong, ground-flush welds is cited as the problem - surely the contractor knew what they were taking on? Have the reporters got it completely wrong?

I will join a number of other websites who seem to parrot each others' news by reporting the shortlist for a new pedestrian bridge design competition in China. This one is for a 400m long structure at Jinsha Lake in Hangzhou, and the invited designers are:

Denton Corker Marshall

Grimshaw

Marc Mimram with Tianjin Urban Planning & Design Institute

Petroff Partnership Architects

Wilkinson Eyre

Zaha Hadid

That's all I know, so if anyone can point me towards more information, that would be appreciated.

27 January 2011

The winner of this contest to design a prototype wildlife bridge in Colorado has been announced: HNTB with Michael Van Valkenburgh & Associates.

When I previously covered the competition finalists, I noted that this design was my favourite, because the structural form is both easy to erect and readily adaptable to different geometries. The bridge has the elevation of a portal frame, but functions as a three-pinned arch, with the two halves of the portal propped against each other at the crown.

Each precast concrete element is in the form of a hyperbolic paraboloid (hypar) shell, which provides high stiffness while being of low weight, hence easy to erect without requiring unduly heavy craneage. The size can be readily amended and multiple units stacked side-by-side to create differently sized wildlife crossings.

"combined brilliantly an overarching focus on wildlife habitat, behavior, and viability with a practical intelligence regarding the making of such a work of infrastructure. The scheme marries well a simple elegance with a brute force. It effectively recasts ordinary materials and methods of construction into a potentially transcendent work of design."

Clearly, they were looking for something practical and modest rather than an architectural statement in its own right.

I wonder whether the winning design has wider applications than just for use in building wildlife bridges. For example, could it substitute for the precast con-arch system sometimes used to cheaply span watercourses, but which lacks the ideal profile for spanning roads and railways? The challenge is in getting the formwork adaptable for precasting a wide range of geometries, and I'm not entirely convinced by the simple diagrams provided above (click on any image for a larger version).

23 January 2011

I'd been looking to get hold of this book since I narrowly missed out on visiting Jürg Conzett's Swiss pavilion at the Venice Biennale last year. "Landscape and Structures: A Personal Inventory of Jürg Conzett" (Scheidegger und Spiess, 272pp, ISBN 978-3858813213, 2010) [amazon.co.uk] presents a travelogue of civil engineering structures throughout Switzerland, drawn from a series of joint trips by Conzett and the photographer, Martin Linsi.

I managed to get a copy from buch.ch, and it's a delightful tome. Divided into chapters both geographically and chronologically (so the early chapters begin with a winter trip, and the final ones in early summer), a wide variety of structures are selected by Conzett for their ability to exemplify successful aesthetic outcomes from an engineering process. They are pretty much all highway, railway or footway structures, from all periods of history, and several examples are of the highways themselves rather than the walls and bridges that support them.

All the structures are photographed in black and white, and accompanied by text both in English and German where Conzett explains various points of interest. A bibliography gives details of further information where it is available. The photos are generally very good, and in several cases quite beautiful, often due to the landscape as much as the structure.

The bridges include everything from historic masonry arch and covered timber spans through to the most recent designs, including several of Conzett Bronzini and Gartmann's own structures. Of the better known structures, Robert Maillart's Salginatobel Bridge is conspicuous by its absence, but it is perhaps over-exposed anyway. The joy here is in the fresh perspective and the exposure of unseen delights.

Much of Conzett's emphasis is on vision and visibility, how a bridge offers a fresh perspective along its length, or how the curve of a road is not merely an exercise in checking sightlines but the opportunity to improve the driver's perspective upon the surrounding landscape. Looking at a seemingly minor retaining wall in the Graubünden, Conzett's attention is drawn to a low-level ledge which both improves driver visibility as well as reducing the apparent height of the wall.

Similarly, the sagging deck curve on Conzett's own Traversinersteg (pictured) is both a means of stiffening the bridge (it allows the deck to react against the prestressing of the support cables) and also a way of reducing the perceived steepness of the bridge's precipitous stairway. This concern for a design that synthesises structural, perceptual, and aesthetic demands, runs through the whole book.

Another welcome aspect is the attention given to designers who have, certainly in English-speaking countries, perhaps been overshadowed by others. Three lovely bridges by Alexandre Sarrasin are included, as is the spectacular Dala Gorge Bridge by Zumofen und Glenz.

My favourite bridge in the whole book is one of the newest, Conzett's Dorfbrücke in Vals, designed with Peter Zumthor. This is a work of purest genius which on first sight appears to be a concrete decked bridge supporting unusual masonry parapets, but in reality is a masonry arch from which a concrete slab is hung, the slab also acting as the arch tie. The engineering is ingenious, but it's the bridge's juxtaposition of brute minimalism and tactile appeal that is most admirable.

This is a very unusual book. It seems at first to be too unstructured a travelogue to hold its appeal, but the combination of excellent photography with Conzett's consistently impeccable judgements makes for a very enjoyable read.

Vaughan's earlier book, "Isambard Kingdom Brunel: Engineering Knight-errant", was a revisionist critique of the widespread view of Brunel as not merely a giant amongst engineers, but very nearly the greatest Briton ever. It drew extensively on archive research to depict a designer who was confrontational, dictatorial, and prone to making over-quick decisions which frequently led to his projects going well over budget. It sought quite consciously to provide a counter-balance to the widely read LTC Rolt biography of Brunel, which by all accounts bought quite deeply into the mythology of a Victorian hero.

It's certainly not news that the Clifton Suspension Bridge wasn't entirely Brunel's design. His initial 1831 proposal didn't start on site until 1836, and money ran out in 1843. Work on the bridge only restarted in 1862, three years after Brunel's death, with the design revised by William Henry Barlow and Sir John Hawkshaw. In part, changes were made to the bridge width and suspension chain arrangement to make use of chains that became available from the recently dismantled Hungerford Suspension Bridge. Changes were also made to the tower design. But the span and general conception remained as Brunel had proposed.

This situation is hardly unusual even today. Is Stonecutters Bridge the design of Halcrow and Flint and Neill, who (like Brunel) won the design competition and developed the basic concept, or of Arup, who completed the detailed design and made various changes to the scheme? And even if one engineer at any of these firms were put forward as the key engineer responsible, how much did they personally contribute?

The modern era, with design tasks shared across a diverse team, is not that different from the Victorian period. Identifying, and lionising, the big names may help personalise history, but essentially it's the engineering version of the lamentable tendency to see national history as the history of royalty. Suggesting that Brunel designed the bridge at Clifton pays proper tribute to the central figure in its creation, while obscuring a more complex reality.

It's also worth considering to what extent Brunel's present-day reputation is based on his forceful personality as much as on his actual engineering achievements. Was he a better engineer than Thomas Telford, Robert Stephenson, or lesser known contemporaries like Thomas Kennard? There seems to me to be an almost willful desire in the popular media to treat Brunel as heroic in the manner of a great general, to gloss over his many flaws and the fact that many of his enterprises were disasters. Like Stephenson, his greatest bridge designs were spectacular and perhaps revolutionary, but rarely of such importance that they became templates for wider adoption.

It's interesting, perhaps, that most popular histories relating to civil engineering are of the royalist type: biographies of the famous names. I can't think, off hand, of any popular books that get to grips with the wider social aspects of the 19th century revolution in scientific bridge design, although there are certainly specialist histories that address it.

Of course, a headline that simply stated "new biography confirms what we already knew in old biographies" is neither going to sell newspapers nor justify a journalist's time and expenses. The need to manufacture controversy is understandable. What I'm less clear on is the underlying need to propagate a heroic mythology, and to defend it against any inquisition, however plausible.

17 January 2011

Jörg Schlaich & Rudolf Bergermann's "Leicht Weit / Light Structures" (Prestel, ISBN 3-7913-2918-9, 2005, 328pp) [amazon.co.uk] is a mammoth coffee-table slab documenting the ever-fertile genius of one of Germany's best known design firms. It came out a few years ago now, an offshoot of a series of exhibitions of Schlaich Bergermann's work held in 2003 to 2005, but I re-read it recently and it more than deserves a mention here.

Schlaich and Bergermann began working together in 1968 in the office of Leonhardt und Andrä, collaborating on a number of television towers, and lightweight structures such as the Munich Olympic stadium roof. In 1980, they set up their own firm, Schlaich Bergermann und Partner. Schlaich had followed his mentor Fritz Leonhardt in becoming a professor at Stuttgart University, and was as prodigious as Leonhardt in his ability to bridge consultancy and academia, contributing to a staggering range of innovative designs.

Presented throughout in dual German and English, the book marries a series of essays with a lengthy survey of SBP's work written by Annette Bögle. The chapter headings give a good idea of quite why SBP are so important: concrete towers; cable net and steel lattice towers; concrete shells; cable nets; grid shells; textile membranes; air-inflated roofs; cable-suspended roofs; highway bridges; railway bridges; footbridges; solar power plants; and more. If they ever deign to descend into the world of mundane civil engineering, little trace of it is to be found in this book.

The essays are generally illuminating, and include contributions from luminaries such as Marc Mimram and David Billington. An interview with Schlaich offers amusement when he is quoted as describing the "wild ones" who "outdo each other with puffed up and squashed blobs, often just satires and caricatures of misinterpreted 'role models' - with no connection between form, function and flow of forces". This is juxtaposed with a picture of a Frank Gehry building design, surely the antithesis of this statement - although, of course, Gehry has often collaborated with SBP.

Schlaich's own essay on lightweight construction identifies it as important for its combination of social, ecological and economic benefits, while clearly noting that it has limits including the paradox that the lightest weight permanent form often requires the heaviest construction methods to build. However, Schlaich sees this as an advantage, particularly where increased labour costs are recognised as beneficial due to the increased employment generated.

Indeed, the essay exemplifies his engineering ethic quite clearly: socially and environmentally aware, an attitude seen both in their early Hooghly Bridge design, with its multitudes of rivets well-adapted to local working requirements, as well as their recent keen interest in solar power structures, and their potential to alleviate energy-poverty at low cost.

"Light Structures" is copiously illustrated with both photographs and diagrams, and the structures included are generally well explained. Most of their best bridges are included although there are some curious omissions such as the Löwentor cable-net footbridge and the Obere Argen Valley Bridge.

Both those were, however, well-covered in Alan Holgate's "The Art of Structural Engineering: The Work of Jörg Schlaich and his Team" (1997), another bulky coffee-table monograph which could be considered to be either competing or complementary. Hopefully I'll cover that one on another occasion.

"Leicht Weit / Light Structures" is an essential book for anyone interested in innovative structural engineering. It's well written and well illustrated, and an excellent survey of some of the most innovative work of the late twentieth century, including in the bridge engineering field.

Max Eyth's "The Bridge Builder" (Sampson Low, 1937, 218pp) is a long out-of-print novelisation of the disaster, originally written in German and published in English translation. I was attracted to it by the back cover blurb, which describes "the deep absorption of the engineer in the wonderful thing that has been conceived in his brain and given material form before his eyes; his artistic delight in the beauty of a perfect mechanical creation; his sense of responsibility for its soundness and durability; all this is set forth with a terse conciseness and a deliberate restraint that are at once emotional and convincing, and give the book undeniable literary value".

Books with a bridge engineer as the central character are few and far between, let alone those claiming to offer special insight, so this seemed like it might be especially interesting to a curious Pontist.

Max Eyth was himself a noted engineer (albeit a designer of agricultural machinery). He appears in the first person in the novel as the narrator of the story of the only barely fictitious "Enno Bridge". However, the main protagonist is one Harold Stoss, a German engineer whose mastery of structural theory is of great service to his employer, William Bruce, civil engineer for the North Flintshire Railway.

Bruce is the stand-in for the bold lead engineer Thomas Bouch, while Stoss's closest real-life counterpart is the Cambridge mathematician Allan Duncan Stewart, who carried out the calculations for the bridge's metalwork and later went on to assist Benjamin Baker in the design of the Forth Bridge.

In the first chapter, Eyth encounters Stoss, and a third German expat engineer, in lodgings in Manchester. As narrator, Eyth reports secondhand on his friend Stoss's experiences, receiving news of developments at the Enno Firth through occasional visits and letters. Only after the bridge is complete does Eyth travel to see it for himself.

All the secondhand reportage gives the book an oddly detached and uninvolving style. Most, if not all, the technical detail is an accurate account of the Tay Bridge story, with a series of bold engineering decisions paving the way for eventual catastrophe. Stoss becomes increasingly anxious about whether he has fulfilled his duties properly, particularly in regard to the treatment of wind load. Speaking of Bruce/Bouch's daughter, he comments that "she kissed me into a lower co-efficient of safety". His mingled joy and fear as he pushes the boundaries of design should be familiar to any engineer who has lain awake late at night pondering the risks associated with innovation.

The engineering is interspersed with plenty of incidental detail, but I still finished The Bridge Builder thinking it was rather unsatisfying. The distancing effect of the uninvolved narrator is the main issue, and the somewhat episodic nature of Eyth's intersections with events leave everything quite disjointed as well.

It would be interesting to see what a more contemporary writer would make of the Tay Bridge story. I can easily imagine it as a courtroom drama, focussing on the real-life debate on where to place the blame. However, although the Tay Bridge Court of Inquiry reached rather firm and unequivocal conclusions, history suggests that the bridge fell for a number of coincident reasons, which may be less suited to the imperatives of drama. A simple re-telling of events might be sufficient, particularly if it got closer to the heart of Bouch himself, who was both the hero and villain of events, with a tragic end.

12 January 2011

Sad news to report - Jolyon Gill, an independent UK bridge engineering consultant who I'm sure several of my readers will know, died yesterday, of a stroke.

Gill worked for Freeman Fox and Partners, the renowned long span bridge designers, and was head of their successor Hyder's special structures group until 2001. He then moved to Faber Maunsell (now part of Aecom) to become their UK head of bridges and special structures. In 2003, a "reappraisal of business objectives" led to his departure, to set up his own firm Jolyon Gill Consultancy Ltd. He was always active in the wider bridge engineering community, for example working on the second edition of the IStructE's guidance manual for bridge access gantries, and serving on the Editorial Advisory Panel for the ICE's Bridge Engineering Journal.

I mentioned him briefly here on a previous occasion, for his talk at a symposium on learning from bridge failures. He struck me as someone both with a sound grasp of the way in which the wider world impacts upon the purely technical, as well as a desire to move beyond conventional wisdom.

11 January 2011

There's already a Bridge of the Month competition which you should take a look at it if you haven't already.

Now there's a new Bridge of the Month newsletter, from Bill Harvey, the masonry arch bridge specialist perhaps best known for his Archie-M arch analysis software. The first issue is available online [PDF] and features Llanelltyd Bridge. It discusses the geometry of the arch, the difference between a three-centred and an elliptical arch, and the difficulty of modelling and hence analysing a bridge with irregular, distorted arch geometry.

08 January 2011

Now, this sounds like just the most fantastic holiday ever, for a pontist so deeply committed as to be practically certifiable.

Eric Sakowski, of the great website highestbridges.com, is organising a three-week trip to China to visit dozens of bridges including the eight highest spans in the world, and many more truly spectacular structures, often in remote parts of the country that Westerners almost never visit.

The tour runs from 5-26 August 2011, and costs less than US$4,000.

Eric's trip preview really has to be read to be believed, and his advice for anyone else looking to make a similar trip is also well worth reading.

07 January 2011

Time is still keeping me from longer posts, so instead, what are the other bridges blogs up to?

Bridge Photo of the Day has returned after an absence of several months, with a series of wintry Alaskan bridges, although sadly it looks like the archive of photos from before their hiatus has disappeared.

My perennial favourite, Tabikappa, seems to visit an inexhaustible supply of interesting bridges in Japan, particularly pedestrian suspension bridges. There was a series of great postings on particularly ramshackle examples that I've mentioned before, but more recent ones have included several unusualasymmetricspans.

Tallbridgeguy is one of the few blogs to discuss bridge design rather than just depict it, and has recently used various posts to focus on the theme of sustainability in bridge engineering.

Frame and Form is an irregular Spanish blog (with English translation). I particularly enjoyed two recentposts on bridges designed by Anta, which are unusual yet simple and attractive.

From Korea, Bridgeworld publishes a wide variety of short features on bridges, often unusual ones. I particularly liked the stressed ribbon bridge examples they showed recently, a variation on this design that's not often seen.

04 January 2011

I'm back from my Christmas break, although blogging may be somewhat subdued as 2011 begins as I have several other things to attend to, New Year's resolutions amongst them.

While I've been away, there have been a couple of interesting items in bridge-related news, chief among them being the New York Port Authority's decision to raise the road deck of the Bayonne Bridge, rather than to build a replacement structure (the third option, raising the bridge and its supporting arch, was surely never a serious contender). At a cost of US$1 billion, this will allow much taller ships to pass below the bridge and access the ports at Newark and Elizabeth. It will be a very challenging project, and definitely one to watch with interest over the next few years.

In the UK, both the big bridges currently under development have had positive news. The £600m Mersey Gateway received government planning consent just before Christmas, about a week after the £2bn new Forth bridge obtained legislative approval from the Scottish Parliament. Both bridge are multi-span cable-stay structures, although they tackle the stability issues of such a design in very different ways. The Mersey span uses a deeper deck to stiffen the towers, while the (significantly longer) Forth crossing has a more innovative solution involving criss-crossing stays near the middle of each span.

Elsewhere, a u-turn by a landowner means that £2.65m of grants earmarked for a new cycle bridge near Perth may never be used.